In recent years, nutritious foods containing minerals etc., which tend to be insufficient for people of today, and produced in consideration of nutritional balance attract attention. They are used not only as conveniently ingestible takeout foods and diet foods, but also as liquid foods for ingestion of nutrition by those who suffer from difficulty in oral ingestion of foods due to advanced age, disease, wound or disability. However, since many of liquid foods are those of low viscosity fluid type, they pose problems of developing gastroesophageal reflux disease, aspiration pneumonia, vomiting, diarrhea, etc. As means for solving such problems, there have been disclosed a method of giving a preliminarily gelled nutritious food (Patent document 1), a method of adding a gelling agent to a nutritious food at the time of ingestion of the food to reduce fluidity of the nutritious food in the stomach (Patent document 2), and a composition containing a polysaccharide, a mineral, and a gas-forming component, which is gelled under the endogastric condition (Patent document 3).
As for other foods, there have been proposed methods of adding phosphoric acid or an organic acid etc. to foods for suppressing aggregation and precipitation of proteins and divalent metal salts (refer to, for example, Patent documents 4 and 5)